Why do my legs feel heavy and swollen at the end of the day?

Heavy, tired, or swollen legs that become worse after standing or sitting for long periods can be associated with chronic venous insufficiency (CVI). CVI occurs when the valves in the leg veins do not effectively move blood back toward the heart, allowing blood to pool in the lower legs. Other conditions can also cause leg swelling, so persistent symptoms should be evaluated by a healthcare professional.